An apparatus for impedance matching of an electrical load to a generator has input connections for connection to the generator and output connections for connection to the load. The apparatus has a converter which connects the input connections to the output connections. An input voltage which is applied between the input connections can be converted into an output voltage. The converter has energy storage means connected to one of the output connections by an active diode, a controllable switching device, and an actuation device. The switching device can be moved to a first and a second switching state so that energy from the generator is stored in the energy storage means in the first switching state. Energy which is stored can be output to the load in the second switching state. A detector is connected to the input connections for detecting a measurement signal for the impedance matching. The actuation device has an activation signal and can be moved to a first and a second operating state. The energy which is output by the generator is temporarily stored in an input capacitor.